Antenna arrangement



Feb. 2, 1932. H. CHIREIX ANTENNA ARRANGEMENT Filed April 28, 1931 fizvenlbr 1%721/ (Zdrezlx a i- 111 2 a Hi 21m;

Patented Feb. 2, 1932 UNITED STATES PArEr -FFICE= ,nnnar onrninx, or PARIsQFRANC QAssI NoR To socinrnrnnnonisn RADIO-ELEC- 'IRIQUE, or PARIS, FRANCE, A CORPORATION or FRANCE whence Eli ANTENNA ARRANGEMENT Application filed April 28, 1931, Serial No.1 533,397, and in France MayB, 1930.

The present invention relates to antenna arrangements and more particularly to. directional antenna arrangements for use on short waves. Q

One of the difliculties met with in the transmission of signals; by means of short waves residesin the manifestation of fading or. vanishing of thesignals. .One of the auses of fading resides in therotation of the plane of polarization of the waves incident on a receiving antenna, the strength of the received signals varying more or less as this plane of polarization differs more or less from the plane of polarization for which the receiving antenna has been constructed.

The object of the present invention is to provide a simple antenna arrangement adapted to receive waves equally well whatever the plane of polarization of said waves may be.

To consider the case of a vertical antenna element half a Wave length long for example, 7

an incident wave whose electric field makes an angle go with the vertical will induce an electromotive force of the form e =A cos it t cos go e =A sin a; t sin (p e +c =A (cos it t cos +sin w t sin co) A cos (as 25+ (p) If this second element is followed by a third element which is again verticaland located one quarter wave length behind the second, that is to say half a wave length behind the first, there will be obtained an electromotive force Finally if there is arranged a fourth element this time horizontal and again one quarter wave length behind the third, that is to say half wave length behind the second, there will be obtained an electromotive force 6; A sin w t sin (p, I

whence It will be seen from the above analysis that in order to combine the electromotive forces induced in the severalv antenna elements the third andfourth elements should beconnect'ed:

in opposition to the first andsecond elements. J

such that the vertical projection of the point B on a horizontal plane passing through A is one quarter wave length behind the P t l i i "It obviously follows, on referringzto F igure 2, that the angle 0 between'AB. and the vertical BB isequal to 30.

A second element BC (Figure 1 and Figure 2) is connected. to the element AB ina horizontal plane but inclined in this plane such that the projection-of the point C. 0n the vertical plane containing the element AB is one-quarter wave length behind the point B. That is to say that theelement BC is inclined to the horizontal line-passing'through B and lying perpendicular to the plane of Figure% at an angle of 30, further elements CD, DE, EF, etc. are arranged in succession in a similar'manner; Y 5

To put the'matter inanother way, the construction of the antenna may be defined by saying that it is constructed'in the form obprism having a square base, whose sides are equal to cos 30, the axis of the prism being parallel to the direction of propagation of the waves, and each linear element g where A is the wave length for which the antenna is designed.

It will easily be seen that such an arrangement fulfills the conditions enumerated above. In eifect the phase of the resultant electromotive force induced in the element having a length equal to BC is displaced by an angle with respect to that induced in the element AB; that induced in the element CD is in phase opposition With that induced inthe element AB (one half wave behind) and so forth. The electromotive force induced in the elements AB and CD both tend to cause current to circulate in the direction of the arrows in accordance with the law of excitation by stationary waves (the phase of the current reverses at each current node, that is to say, at each peak).

The number of elements is not limited to that illustrated and the greater the number of elements employed the more is the directive effect of the antenna accentuated.

In the case of an incident wave arriving perpendicular to the plane of Figure 1, the elements AB CD EF GH etc. constitute in effect an alignment of antenna the effects of which are additive. Similarly the elements BC ED FG HI constitute a second alignment at right angles to the first, giving a concentration in the vertical plane. The distance in the direction of propagation of the wave between AB and CD being one half wave length or between AB and EF a whole wave length, such an antenna does not act as a reflector inasmuch as it receives equally well waves which are incident at either end thereof.

The energy received may be tapped by any suitable coupling preferably in the middleof the conductor ABODEFGHI etc.

Naturally such an antenna may equally well be employed for transmission. Obviously the structure described above may be turned round on its longitudinal axis through any angle so that the elements AB and BC in place of being alternately horizontal and vertical are disposed obliquely. The

7 only condition to be fulfilled is that the direction of propagation of the radiation to be received or transmitted should be parallel to the longitudinal axis of the antenna.

I A plurality of identical systems may be employed in combination further to increase the directive properties thereof.

It should be understood moreover that the square coil structure does not exclude variations producing equivalent effects. The wire may be wound on any prism having a regular polygonal base or even on a circular cylinder, the essential and general condition to be observed being that the length of one turn of the developed coil should be twice the length of the wave and the pitch of the coil equal to the length of the wave, the orientation of the axis of the coil being that of the propagation of the wave.

Claims:

1. Aerial comprising a number of series connected sections in the form of an helix each Winding of which has a perimeter equal to twice the wavelength and the pitch of which is equal to one wavelength.

2. Aerial comprising a number of series connected equal sections, the length of each section being equal to half a wave length, each section lying in a plane at right angle with the plane of the preceding section andthe whole forming an helix the pitch of wavelength.

which is equal to one HENRI CHIR-EIX. 

